OS X Lion 10.7.5 is the latest and most fully-featured update to this version of Apple's operating system as of 2015. The 10.7.5 update enhances many features of OS X Lion, including improvements to Wi-Fi connectivity and projector compatibility. The update also includes several security fixes.
OS X Lion 10.7.5 fixes a security issue related to bash shell commands, a potentially serious exploit that could allow a hacker to run programs remotely on previous versions of Lion. The update also fixes problems with accessing secure websites through proxy servers and updating wireless networking passwords in the operating system's key chain storage.